Abstract: In the process of engineering construction in complex urban areas, underground hidden faults bring great difficulties and safety hazards to engineering construction and later operation. This paper applies the opposing coils transient electromagnetic method(OCTEM), which has a strong anti-interference ability and is less limited by the site, to the detection of hidden faults in a complex area of a subway tunnel project in Shenzhen. Based on the inversion resistivity cross-section map, the plan position and occurrence of hidden faults in this area are inferred. Finally, the effectiveness of this method in detecting hidden faults in this areas is verified through comparative analysis with geological drilling data. This paper has certain referencial significance for detecting hidden faults in complex urban areas.